\documentclass[a4paper]{article}

\usepackage{graphicx}
\usepackage{booktabs}
\usepackage{longtable}
\usepackage{array}
\usepackage{color}
\usepackage{fontspec}
\usepackage[colorlinks,linkcolor=black]{hyperref}
\usepackage{multicol}


% xetex
\newcommand\fontnamehei{Adobe Heiti Std}
\newfontinstance\HEI{\fontnamehei}
\newcommand{\hei}[1]{{\HEI #1}}

\title{The Third Homework of Software Engineering }

\author{Kai Yan\hei{(颜开)} \\ 071251184}
\date{\today}

\begin{document}
\maketitle

\begin{center}
\begin{longtable}{|lm{0.2\textwidth}|lm{0.2\textwidth}|lm{0.2\textwidth}|}
\toprule
No. & Answer & No. & Answer & No. & Answer \\
\midrule
1 & E & 11 & G & 21 & D \\
2 & D & 12 & A & 22 & C \\
3 & C & 13 & G & 23 & E \\
4 & False & 14 & G & 24 & B \\
5 & True & 15 & B & 25 &  True \\
6 & True & 16 & F & 26 & C \\
7 & True & 17 & False & 27 & True \\
8 & True & 18 & E & 28 & F \\
9 & True & 19 & C & 29 & A \\
10 & True & 20 & D & 30 & D \\
\bottomrule
\caption{the Questions} \\
\end{longtable}
\end{center}

\end{document}
